Open Access

ARTICLE

Calculation of the Gas Injection Rate and Pipe String Erosion in Nitrogen Drilling Systems

by Mingren Shao¹, Chunpeng Wang¹, Degui Wang¹, Wenbo Mei¹, Mingjie Li¹, Hao Yang^2,*

1 China United Coalbed Methane Corporation, Ltd., Beijing, 100011, China
2 School of Engineering and Technology, China University of Geosciences (Beijing), Beijing, 100083, China

* Corresponding Author: Hao Yang. Email:

Fluid Dynamics & Materials Processing 2022, 18(2), 417-430. https://doi.org/10.32604/fdmp.2022.018012

Received 23 June 2021; Accepted 17 August 2021; Issue published 16 December 2021

Abstract

Detailed information is provided for the design and construction of nitrogen drilling in a coal seam. Two prototype wells are considered. The Guo model is used to calculate the required minimum gas injection rate, while the Finnie, Sommerfeld, and Tulsa models are exploited to estimate the ensuing erosion occurring in pipe strings. The calculated minimum gas injection rates are 67.4 m³/min (with water) and 49.4 m³/min (without water), and the actual field of use is 90–120 m³/min. The difference between the calculated injection pressure and the field value is 6.5%–15.2% (formation with water) and 0.65%–7.32% (formation without water). The results show that the Guo model can more precisely represent the situation of the no water formation in the nitrogen drilling of a coal seam. The Finnie, Sommerfeld, and Tulsa models have different sensitivities to cutting densities, particle size, impact velocity and angle, and pipe string hardness.

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Keywords

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